Use of at least a fatty ester for preparing a composition designed to inhibit 5-$g(a)-reductase activity, in pharmacology, in particular dematology, in cosmetics and as food additive

ABSTRACT

The invention concerns the use of at least a fatty ester for preparing a composition designed to inhibit 5α-reductase activity. Said use produces a remarkable inhibiting effect of 5α-reductase thereby providing a novel response for treating dermatological pathologies and/or disorders related to congenital or acquired exaggeration of 5α-reductase activity, in particular for treating prostatic hypertrophy, prostatic adenoma, acne, hyperseborrhea, alopecia and hirsutism. The invention also concerns cosmetic treatment methods, in particular for greasy skin, and the use of said fatty esters as additives in a food product for human and/or animal consumption.

[0001] The present invention relates to the use of at least one fattyester for preparing a composition designed to inhibit 5α-reductaseactivity, in particular for treating prostatic hypertrophy, prostaticadenoma, acne, hyperseborrhea, alopecia and hirsutism. The inventionalso relates to methods for cosmetic treatment, in particular of greasyskin, and the use of the fatty esters described as additives in a foodproduct for human and/or animal consumption.

[0002] 5α-Reductase is a NADPH-dependent microsomial enzyme which existsin the form of two isoenzymes synthesized from two different genes. The5α-reductase type 1 isoenzyme is essentially found in the liver and theskin, more particularly in the sebaceous glands of nongenital skin andof the scalp, and appears at puberty. The type 2 isoenzyme ispredominant in the prostate and in the skin of differentiated sexualareas: genital region, beard, and plays a role in sexualdifferentiation. The distribution of the 5α-reductase types 1 and 2isoenzymes in the skin and cutaneous annexes in humans may beillustrated by the following table.

[0003] Table 1: Distribution of the 5α-Reductase Types 1 and 2Isoenzymes in the Skin and Cutaneous Annexes in Humans H5- r1 H5- r2EPIDERMIS Basal layer ++ + Spinous layer + ++ Granular layer + − Hornylayer − − DERMIS Fibroblasts ++ − SEBACEOUS GLANDS Basal cells ++ +Glandular cells ++ − ECCRINE SWEAT GLANDS Excretory canal − − Secretarycells ++ − Myoepithelial cells ++ + HAIR FOLLICLE Dermal papilla + +?Cells of the matrix ++ + Inner epithelial sheath ± +++ Outer epithelialsheath ++ − Arrector muscle + −

[0004] A number of pathologies exist for which a congenital or acquiredexaggeration of the 5α-reductase activity is completely or predominantlyresponsible for the disorders observed.

[0005] For example, in humans, this 5α-reductase enzyme, mainly locatedin the genital tissues and in the skin, catalyzes the hydroxylation oftestosterone to 5α-reductase dihydrotestosterone (DHT). However, sinceDHT is an androgen which is much more active than testosterone (abouttwice as much), the effects of the latter are amplified in tissues whereDHT is produced. An excessively high activity of 5α-reductase thuscauses excessively high levels of androgen in the form of DHT in theprostate, hence an overstimulation of the latter resulting in anundesirable growth which can lead to the pathology of prostatichypertrophy, or even to prostatic adenoma, most often requiring asurgical operation.

[0006] Other pathologies, of the dermatological type, may be observed inmen or women as resulting from an overactivity of 5α-reductase, namelyin particular acne, hirsutism or alopecia.

[0007] In the skin, the 5α-reductase activity is higher in the sebaceousgland than in other structures. Moreover, the seborrheic glands show ahigher 5α-reductase activity than those of other skin areas.Consequently, the level of physiological sebaceous secretion appears tobe closely linked to the activity of this enzyme.

[0008] In acne sufferers, a hyperactivity of 5α-reductase exists. Morethan an increase in the serum androgen levels it is an increase in theprecursors of DHT, main factor for the sebaceous function, whichparticipates in acne. Greasy or seborrheic skin, apart from itsunsightly appearance, constitutes a ground on which complications mayoccur. It affects the regions where the sebaceous glands are numerousand mainly results from an androgenic overstimulation of sebaceousproduction by these specific glands. Hyperseborrhea participates in theonset of lesions caused by acne vulgaris.

[0009] In the scalp, the 5α-reductase type 1 isoenzyme is found in thesebaceous glands, as well as in the hair follicle. The 5α-reductase type2 isoenzyme is predominantly located in the inner epithelial sheath, andin the dermal papilla of the hair. However, this latter location remainsto be specified.

[0010] Androgenic alopecia, whose physiopathogeny is very similar tothat of acne, is the most frequent of alopecias and undoubtedly that inwhich the demand for therapy is the greatest. 5α-Reductase appears toplay a key role in this pathology. Indeed, men affected by a geneticdeficiency in 5α-reductase type 2 isoenzyme do not develop androgenicalopecia.

[0011] Taking into account the preceding text, research has beendirected toward the development of 5α-reductase inhibitors. Somesteroids such as progesterone have been tested in this context, but itsrapid metabolization makes it ineffective in vivo. To be active, the5α-reductase inhibitor should be sufficiently stable in order to blockthe activity of the enzyme in vitro. Finasteride, a competitivesteroidal inhibitor, fulfils this condition, but it is more active onthe type 2 isoenzyme than on the type 1 isoenzyme and these twoisoenzymes have only 50% homology on their amino acid sequence. It istherefore especially in benign hyperplasia of the prostate thatfinasteride has already been tested.

[0012] Moreover, Serenoa Repens extract is is also known as reference asa 5α-reductase inhibitor, the Serenoa Repens extract having theadvantage, compared with finasteride, of a natural origin as a plantextract, allowing better comparison for products tested which are alsoof natural origin. Serenoa Repens, also known by the name Sabalserrulatum, is a small palm tree which is found in the United States(Florida), in North Africa and in Spain.

[0013] It has now been found, quite surprisingly and unexpectedly, thatthe use of certain compounds, fatty esters, makes it possible to obtaina remarkable 5α-reductase activity inhibiting effect, thus providing inparticular a novel response for the treatment of the dermatologicalpathologies and/or disorders mentioned above.

[0014] The present invention thus relates to the use of at least onefatty ester for preparing a composition designed to inhibit 5α-reductaseactivity.

[0015] In particular, the use according to the invention ischaracterized in that the composition is designed to inhibit the5α-reductase type 1 isoenzyme and/or type 2 isoenzyme.

[0016] The expression “fatty ester” is understood to mean according tothe invention, in accordance with the general knowledge of personsskilled in the art, a molecule comprising at least one ester functionalgroup and at least one “fatty” hydrocarbon chain, that is to say alinear hydrocarbon chain of at least 7 carbon atoms.

[0017] The fatty ester which can be used according to the inventioncomprises at least one ester functional group and at least one fattychain, the ester functional group comprising a C₁-C₃₀ alkoxy group whosehydrocarbon chain is linear or branched, optionally substituted with oneto 3 hydroxyl groups, and the fatty chain being a linear C₇-C₃₀hydrocarbon chain containing between 0 and 2 ethylenic unsaturations,optionally substituted with 1 to 3 hydroxyl groups and/or 1 to 3 esterfunctional groups (of course in addition to the principal esterfunctional group).

[0018] In particular, the ester functional group may comprise a C₁-C₂₂,and more particularly C₁-C₁₈, alkoxy group, as in the case of amonoglyceride (glycerol monoester) and/or may be a branched chain suchas, for example, an isopropyl or isobutyl.

[0019] The fatty chain is preferably an ethylenically unsaturated linearC₇-C₃₀ hydrocarbon chain comprising 1 or 2 conjugated or nonconjugatedethylenic unsaturations, as for example in the case of methyl linoleate.

[0020] The fatty chain may advantageously comprise in particular from 1to 22, and more particularly from 1 to 18 carbon atoms.

[0021] The preparation of the fatty esters which can be used accordingto the invention falls within the methods known to persons skilled inthe art. The methods for preparing esters not cited in the text whichfollows but which form part of the general knowledge of persons skilledin the art may therefore also be used.

[0022] Of course, there may be mentioned, firstly, the esterification ofa fatty acid whose fatty chain corresponds to that of the desired fattyester, with the alcohol whose hydrocarbon part corresponds to that ofthe alkoxy group of the desired fatty ester.

[0023] The formation of the esters from the carboxy acids and thealcohols may be carried out either directly, or by converting the acidto more reactive derivatives, or by activating the alcohol for acondensation with the carboxylate.

[0024] The direct esterification of a carboxylic acid with an alcohol isa balanced reaction, catalyzed by strong protonic acids. The reaction iscarried out with a large excess of alcohol in a solvent which forms anazeotrope removed by distillation. The methyl esters may be obtainedfrom solutions of hydrochloric methanol at 5% or sulfuric methanol at1-3%. It is possible to use Lewis acids as catalysts. The specific caseof direct esterification between a fatty acid and glycerol in thepresence of homogeneous or heterogeneous acid catalysts may also bementioned.

[0025] The activation of the carbonyl consists in converting thehydroxyl to a better leaving group. The acid chlorides are thederivatives most frequently used. The use of acid anhydrides may also bementioned.

[0026] The activation of the alcohol consists in making it more reactivetoward a nucleophilic attack by the carboxylate ion. The diazomethane isa very reactive source of methyl after deprotonation of the acid.

[0027] Finally, the esterification of the carboxylic acids may also becarried out by the enzymatic route. Lipases catalyze the esterification.These lipases are obtained from microorganisms of the generaAspergillus, Candida, Geotrichum, Mucor, Penicillium.

[0028] Moreover, the fatty esters which can be used according to theinvention may be prepared by transesterification which is a reactionbetween an ester and an alcohol leading to a different ester. Threetypes of reaction are grouped under the term transesterification:

[0029] alcoholysis which is a reaction between an ester and an alcohol;

[0030] acidolysis which is a reaction between an ester and a carboxylicacid (or an acid anhydride);

[0031] interesterification which is an exchange reaction between twoesters, of the nonalkoxy groups.

[0032] The transesterification is advantageously catalyzed byhomogeneous or heterogeneous catalysis.

[0033] Numerous homogeneous (acid or base) catalysts are described inthe literature. The acid catalysts may be strong inorganic acids such assulfuric, sulfonic, phosphoric or hypochloric acid, but also organicacids such as para-toluenesulfonic or methanesulfonic acid. The basecatalysts commonly used in transesterification are conventional basessuch as hydroxides (sodium hydroxides or potassium hydroxides),carbonates (K₂CO₃, Na₂CO₃) and alcoholates (NaOCH₃, NaOEt).

[0034] In heterogeneous catalysis for transesterification, it ispossible to use Lewis acids, but they are generally not very active. Ithas also been shown that tributyltin alcoholate (Bu₃SnOR) could catalyzethe transesterification reaction between an alcohol and an ester at 120°C. for an alcohol/ester molar ratio of 10. Titanium alcoholates(Ti(OR)₄) have been used for a long time in industry as activetransesterification catalysts. However, it is necessary to hydrolyzethem and to filter them at the end of the reaction in order to removethem from the reaction medium. In particular, supported titanates haveproved active during methanolysis of the soybean oil.

[0035] Among the other catalysts which can be used for a heterogeneouscatalysis of transesterification, there may also be mentionedguanidines, lanthanides, enzymes such as lipases like Pseudomanos sp orMercor Miehei, alkaline-earth metal oxides, magnesium oxide and finallysupported catalysts such as basic centers (calcium oxide) supported onvaried oxides (magnesium oxide, alumina, silica and the like).

[0036] Heterogeneous catalysis has the advantages, compared withhomogeneous catalysis, of using catalysts which can be more easilyseparated from the reaction medium and of causing fewer problems ofcorrosion and of side reactions.

[0037] The starting materials for the esterification reactions describedabove may be of synthetic or natural origin, in particular of animal orplant origin.

[0038] Fatty substances of plant or animal origin are preferred asstarting materials which provide the fatty chain of the fatty estersused according to the invention.

[0039] It is thus possible to carry out an esterification as describedabove of a fatty acid, in particular of plant origin, with an alcohol.

[0040] Among the fatty acids which can be used for these esterificationreactions, there may be mentioned in particular the fatty acids obtainedfrom fatty acid soaps which are by-products of the saponification of avegetable oil. This indeed involves a very advantageous enhancement ofthe value of these by-products of the preparation of the unsaponifiablecomponents of vegetable oil.

[0041] Among the vegetable oils which may be used, there may bementioned in particular sunflower, palm, palm kernel, coconut,grape-seed, black mustard, poppy-seed, karite butter, sweet almond,soybean, avocado, lupine, peanut, cottonseed, sesame, olive, corn,cocoa, castor, ben, linseed, colza, annatto, wheat germ, safflower, nut,hazelnut and rapeseed oil. Avocado oil and soybean oil are particularlypreferred.

[0042] The saponification of the oil, in particular of avocado (orsoybean) oil is an essential step of the method for producingunsaponifiable components. This step, which is carried out in thepresence of aqueous potassium hydroxide and ethanol, is a basichydrolysis of the oil (triglycerides) leading to the formation ofpotassium soaps and glycerol:

[0043] The unsaponifiable component, in emulsion in theaqueous-alcoholic phase (“soapy” phase), is then extracted withdichloroethane (DCE) according to a liquid-liquid extraction method.After extraction, the aqueous-alcoholic phase, freed of theunsaponifiable fraction, is a mixture consisting essentially of soaps,ethanol, water, glycerol, DCE and fraction I. Fraction I is one of thecomponents of the unsaponifiable component of avocado. It constitutessubstrates having a fatty alkyl chain (radical R) and hydroxylfunctional groups:

RCH₂—CH(OH)CH₂CH(OH)CH₂OH

[0044] These hydroxylated compounds are partially soluble in theaqueous-alcoholic phase.

[0045] After the liquid-liquid extraction step, the “soapy” phase isacidified with sulfuric acid. The soaps are then converted to fattyacids (reaction 1 below). The mixture obtained is then distilled so asto remove the ethanol and the traces of DCE. The fatty acids and thewater are finally separated by decantation.

2RCOO⁻K⁺+H₂SO₄→2RCOOH+K₂SO₄  (1)

[0046] These crude avocado fatty acids are finally purified, for exampleon a silica column (eluent hexane and then hexane-diethyl ether 95:9) orby molecular distillation and may thus constitute the raw material usedduring the synthesis of the avocado fatty esters, in particular of theavocado methyl esters. The fatty acids of soybean or of anothervegetable oil such as those cited above may be obtained according to thesame route of synthesis.

[0047] Thus, according to a particular embodiment, the fatty ester usedaccording to the invention is obtained by esterification of at least onefatty acid of at least one vegetable oil, it being understood that theexpression “vegetable oil fatty acid” covers according to the inventionthe fatty acids originally present in said vegetable oil and the fattyacids which may be obtained by treating the soapy phase aftersaponification of said vegetable oil, as described above.

[0048] The triglycerides present in the fatty substances of plant origin(in particular vegetable oils) or of animal origin (in particular fishoils) may also represent a non-negligible source of fatty esters whichcan be used according to the invention, via a transesterification usingmeans known to persons skilled in the art as described above.

[0049] Thus, according to another particular embodiment, the fatty esterused according to the invention is obtained by transesterification ofthe triglycerides of at least one vegetable oil, as described above.

[0050] Regardless of the route of synthesis selected, a fatty ester isadvantageously used according to the invention which is chosen from thegroup consisting of fatty esters of avocado and soybean oil and mixturesthereof.

[0051] More particularly, the fatty ester consists of alkyl esters ofavocado oil, alkyl esters of soybean oil and a mixture thereof. Theexpression “alkyl esters of avocado oil” (respectively “alkyl esters ofsoybean oil”) is understood to mean according to the invention a mixtureof fatty esters obtained by esterification of fatty acids of avocado oil(respectively of soybean oil), fatty acids which have been obtained bytreating the soapy phase after saponification of the avocado oil(respectively soybean oil) and then subjected to an esterification withat least one alcohol or a mixture of alcohols, whose alkyl groupdetermines the “alkyl” part of these alkyl esters. For example, the useof butanol thus makes it possible to obtain “butyl” esters. Preferably,an alcohol is used which has from 1 to 6 carbon atoms, whose alkyl groupis linear or branched, such as for example isopropanol. It is of courseunderstood that this definition covers the use, for such anesterification, of a mixture of alcohols as already mentioned above, forexample of a mixture of butanol and methanol. Preferably still, such anesterification is carried out with a catalytic mixture, in particular aBF₃/ethyl ether mixture.

[0052] More particularly, the fatty ester consists of methyl esters ofavocado oil, methyl esters of soybean oil or a mixture thereof. Theexpression “methyl esters of avocado oil” (respectively “methyl estersof soybean oil”) is understood to mean according to the invention amixture of fatty esters obtained by esterification of fatty acids ofavocado oil (respectively soybean oil), the fatty acids having beenobtained by treating the soapy phase after saponification of the avocadooil (respectively soybean oil) and then subjected to esterification withmethanol, preferably with a catalytic mixture, in particular a BF₃/ethylether mixture.

[0053] Still more particularly, the fatty ester consists of butyl estersof avocado oil, butyl esters of soybean oil or a mixture thereof. Theexpression “butyl esters of avocado oil” (respectively “butyl esters ofsoybean oil”) therefore is understood to mean according to the inventiona mixture of fatty esters obtained by esterification of fatty acids ofavocado oil (respectively soybean oil), the fatty acids having beenobtained by treating the soapy phase after saponification of the avocadooil (respectively soybean oil) and then subjected to esterification withbutanol, preferably with a catalytic mixture, in particular a BF₃/ethylether mixture. The butyl esters of avocado and soybean oils arecharacterized as follows:

[0054] Butyl Esters of Avocado Oil Contents of butyl esters 95% min.Acid value <5 Residual unsaponifiable component <0.5 wt % Distributionof fatty acids: Palmitic acid C16 12 to 25% Palmitoleic acid C16′  3 to10% Stearic acid C18 traces Oleic acid C18′ 45 to 75% Linoleic acid  6to 18% Linolenic acid C18′ <5%

[0055] Butyl Esters of Soybean Oil Content of butyl esters 95% min. Acidvalue <5 Residual unsaponifiable component <0.5 wt % Distribution offatty acids: Myristic acid C14 <0.2% Palmitic acid C16  9 to 13%Palmitoleic acid C16′ <0.3% Stearic acid C18 3 to 5% Oleic acid C18′ 17to 30% Linoleic acid C18″ 48 to 58% Linolenic acid C18′ ″  5 to 11%Arachidic acid C20 <1% Eicosenoic acid C20′ <1% Behenic acid C22 <1%

[0056] According to another particularly preferred embodiment of thepresent invention, at least one fatty ester is used which is chosen fromthe group consisting of methyl oleate, methyl linoleate, methylstearate, methyl laurate, methyl undecylenate, butyl oleate, oleyloleate, methyl ricinoleate, methyl palmitate, methyl palmitoelate, andmixtures thereof.

[0057] According to the invention, the fatty ester as described above isused in a proportion of between about 0.001 and about 100% by weight(use in pure form, for example as an emollient), preferably betweenabout 0.01 and about 70% by weight, and still more particularly betweenabout 0.1 and 10% by weight, relative to the total weight of thecomposition.

[0058] The composition prepared by the use according to the inventionmay, in addition, comprise a pharmaceutically, dermatologically orcosmetically acceptable excipient. It is possible to use any excipientsuitable for galenic forms known to persons skilled in the art foradministration by the topical, oral, enteral or parenteral, inparticular rectal, route.

[0059] In particular, this excipient may be suitable for the productionof a composition in the form of an oily solution, of a water-in-oilemulsion, an oil-in-water emulsion, a microemulsion, an oily gel, ananhydrous gel, a cream, a dispersion of vesicles, of microcapsules or ofmicroparticles, or alternatively of hard gelatin capsules or of plant orsoft gelatin capsules.

[0060] Preferably, an excipient is used which is suitable foradministration by the external topical route or by the rectal route.

[0061] The advantageous effect of inhibition of the 5α-reductaseactivity provided by the use according to the invention makes itpossible to design the composition thus prepared for therapeutic, inparticular dermatological, and cosmetic treatments.

[0062] Thus, the use according to the invention is characterized in thatthe composition is designed for treating skin pathologies and/ordisorders related to congenital or acquired exaggeration of 5α-reductaseactivity.

[0063] In particular, the use according to the invention ischaracterized in that the composition is designed for treating prostatichypertrophy.

[0064] In addition, the use according to the invention is characterizedin that the composition is designed for treating prostatic adenoma.

[0065] The use of an excipient suitable for administration by the rectalroute as described above may be particularly envisaged for thesetreatments of prostatic hypertrophy and/or adenoma.

[0066] The use according to the invention is also characterized in thatthe composition is designed for treating acne.

[0067] The use according to the invention is also characterized in thatthe composition is designed for treating hyperseborrhea.

[0068] Finally, the use according to the invention is also characterizedin that the composition is designed for treating alopecia.

[0069] The use according to the invention is also characterized in thatthe composition is designed for treating hirsutism.

[0070] The subject of the present invention is also a method for thecosmetic treatment of greasy skin, characterized in that a cosmeticcomposition containing at least one fatty ester as described above isapplied to the skin.

[0071] The subject of the invention is moreover a method for thecosmetic treatment of hair loss, characterized in that a cosmeticcomposition containing at least one fatty ester as described above isapplied to the scalp.

[0072] Finally, the subject of the invention is also a method for thecosmetic treatment of excess pilosity, characterized in that a cosmeticcomposition containing at least one fatty ester as described above isapplied to the regions of the skin exhibiting excess pilosity.

[0073] In fact, unlike hormonal medical treatments, the latter twomethods of cosmetic treatment make it possible to improve the appearanceby visibly reducing the unsightly phenomena of hair loss related toalopecia and the phenomena of excess pilosity related to hirsutism.

[0074] According to a preferred embodiment of these methods of cosmetictreatments, the fatty ester is present in the composition in aproportion of between about 0.001 and about 100% by weight (use in pureform, without excipient, for example as an emollient), preferablybetween about 0.01 and about 70% by weight, and still more particularlybetween about 0.1 and 10% by weight, relative to the total weight of thecomposition.

[0075] Advantageously, the cosmetic composition applied according to thecosmetic method of the invention contains, in addition, at least onecosmetically acceptable excipient as described above.

[0076] Finally, the subject of the invention is furthermore the use ofat least one fatty ester, as described above, as additive in a foodproduct for human and/animal consumption. This food use is preferablycharacterized in that the fatty ester is present in the food in aproportion of between about 0.001 and about 100% by weight, preferablybetween about 0.01 and about 70% by weight, and still more particularlybetween about 0.1 and 10% by weight, relative to the total weight of thefood.

[0077] The following examples are intended to illustrate the presentinvention and should not in any case be interpreted as being capable oflimiting the scope thereof.

[0078] Unless otherwise stated, the percentages indicated in thefollowing examples are percentages by weight.

Example 1 Preparation of Methyl Esters of Avocado Oil and of Soybean Oil

[0079] Methyl esters of avocado oil and of soybean oil are preparedaccording to the following procedure:

[0080] 1. Production of Purified Avocado and Soybean Fatty Acids

[0081] The saponification of avocado (or soybean) oil is an essentialstep of the method for producing unsaponifiable components. This step,carried out in the presence of aqueous potassium hydroxide and ethanol,is a basic hydrolysis of the oil (triglycerides) leading to theformation of potassium soaps and of glycerol:

[0082] The unsaponifiable component, in emulsion in theaqueous-alcoholic phase (“soapy” phase), is then extracted withdichloroethane (DCE) according to a liquid-liquid extraction method.After extraction, the aqueous-alcoholic phase, freed of theunsaponifiable fraction, is a mixture consisting essentially of soaps,ethanol, water, glycerol, DCE and fraction I. Fraction I is one of thecomponents of the unsaponifiable component of avocado. It consists ofsubstrates having a fatty alkyl chain (radical R) and hydroxylfunctional groups:

RCH₂—CH(OH)CH₂CH(OH)CH₂OH

[0083] These hydroxylated compounds are partially soluble in theaqueous-alcoholic phase.

[0084] After the liquid-liquid extraction step, the “soapy” phase isacidified with sulfuric acid. The soaps are then converted to fattyacids (reaction 1). The mixture obtained is then distilled so as toremove the ethanol and the traces of DCE. The fatty acids and the waterare finally separated by decantation.

2RCOO⁻K⁺+H₂SO₄→2RCOOH+K₂SO₄  (1)

[0085] These crude avocado fatty acids are finally purified on a silicacolumn (eluent hexane and then hexane-diethyl ether 95:5) and therebyconstitute the raw material used during the synthesis of the avocadomethyl esters.

[0086] The soybean fatty acids are obtained according to the same routeof synthesis.

[0087] 2. Preparation of the Methyl Esters of Avocado Oil and of SoybeanOil

[0088] The methyl esters of avocado are obtained according to thefollowing procedure:

[0089] 250 ml of methanol, 500 g of avocado fatty acids and 12.5 ml of aBF3/ethyl ether mixture are mixed in a three-necked round-bottomed flaskequipped with a condenser and magnetic stirring. The reaction mixture isthen heated under reflux for 1 hour.

[0090] The methyl esters thus obtained are dried under vacuum in arotary evaporator and then finally purified by molecular distillation,at 120° C. under a vacuum of 4 μm of mercury and with a distillationrate of 90%.

[0091] The soybean fatty esters are obtained according to the same routeof synthesis.

[0092] It is also possible, for example, to obtain butyl esters ofavocado oil and of soybean oil respectively according to the same routeof synthesis except that methanol is replaced with butanol (see example6 of composition below).

[0093] 3. Analysis of the Products Obtained

[0094] 3.1 Composition of the Purified Avocado Fatty Acids TABLE 2Content of fatty acids 96.2% Residual unsaponifiable component 3.8%Distribution of fatty acids: Myristic acid C14:0 0.08% Palmitic acidC16:0 22.7% Palmitoleic acid C16:1 9.9% Stearic acid C18:0 0.6% Oleicacid C18:1 50.3% Linoleic acid C18:2 11.8% Linolenic acid C18:3 0.9%

[0095] 3.2 Composition of the Avocado Methyl Esters TABLE 3 Methylesters of fatty acids 86.0 Residual unsaponifiable component 2.1Components not determined 11.9 Distribution of fatty acids: Palmiticacid C16:0 25.1% Palmitoleic acid C16:1 8.4% Stearic acid C18:0 0.6%Oleic acid C18:1 55.8% Linoleic acid C18:2 9.1% Linolenic acid C18:30.4%

[0096] 3.3 Composition of the Soybean Methyl Esters TABLE 4 Methylesters of fatty acids 97.8 Residual unsaponifiable component —Components not determined 2.2 Distribution of fatty acids: Palmitic acidC16:0 20.4% Palmitoleic acid C16:1 0.2% Stearic acid C18:0 2.9% Oleicacid C18:1 20.9% Linoleic acid C18:2 49.8% Linolenic acid C18:3 2.8%

Example 2 Evaluation of the Inhibitory Activity on the 5α-ReductaseActivity by Measuring the Quantity of 5-Dihydrotestosterone Formed FromTestosterone by DU145 Cells

[0097] 1. Materials and Methods

[0098] 1.1 Materials

[0099] The prostatic cells DU145 are derived from a tumor line obtainedfrom a prostate carcinoma (ATCC No. HTB 81). The MEM medium (ref.0410265), the glutamine and the gentamycin are from Gibco. The fetalcalf serum (FCS) is from DAP and is used decomplementized (45 mm at 56°C.). The plastics serving for the culture (dishes and plates) are fromCostar. The testosterone is from Sigma.

[0100] 1.2 Method

[0101] 1.2.1 Preparation of the Product Ranges

[0102] A stock solution in ethanol at 10 mg/ml is prepared from each ofthe products tested.

[0103] The concentration range used for the experiments is thefollowing: 0, 5, 10, 50, 100 and 500 micrograms/ml. (Dilution performedin the culture medium).

[0104] The volume of extract added per well being 20 microliters/well,the solutions to be prepared are concentrated 50×.

[0105] Preparation of Testosterone

[0106] A stock solution of testosterone at 10 mM is prepared in ethanol.At the time of its use, this solution is diluted 1:1 000 in the culturemedium and 10 microliters are added per well.

[0107] 1.2.2 Experiment of Inhibition of the 5α-Reductase of DU145 Cells

[0108] The prostatic cells DU145 are cultured at 37° C., 5% Co₂ in anMEM medium containing glutamine (2 mM), gentamycin (50 micrograms/ml)and 10% FCS. Their subculture rate is 1:10.

[0109] Before starting the experiment, the cells are placed in culturein 6-well plates at the rate of 2×10⁵ DU145 cells per well/1 ml ofmedium containing only 1% FCS. The cells are maintained for 3 days at37° C., 5% CO₂. On the day of the experiment, the culture mediumcontained in the wells is removed and replaced with fresh mediumcontaining 1% FCS. The testosterone (0.1 micromolar final) as well asthe extracts at the different concentrations are added to the medium atthe rate of 10 to 20 microliters/well respectively. (The “control” wellscorrespond to cells incubated in the presence of testosterone and of oneequivalent ethanol. This makes it possible to substract the effect ofthe solvent on the cultures and to determine the percentage of DHTformed in the absence of inhibitor). The cells are then incubated at 37°C., 5% CO₂. After 3 hours, the culture supernatants are collected andfrozen at −80° C. until assayed.

[0110] Measurement of the Quantity of DHT Formed

[0111] Principle: extraction of the lipophilic products with ether,concentration of the samples with respect to DHT by affinitychromatography and radioimmunological assay.

[0112] Preparation of the Samples

[0113] After having vortexed the samples, introduce the samples into“SEPEX” flasks

[0114] Add to each tube 0.1 ml of radioactive solution “3H-Rdt” (forevaluation of the extraction yield). Close the flasks, vortex them oneby one.

[0115] Allow to stand for 30 min at room temperature. Then vortex eachflask again.

[0116] Add to each flask: 5 ml of diethyl ether.

[0117] Close the flasks and manually shake them vigorously. Allow tosettle for a few minutes.

[0118] Freeze the aqueous phases at −30° C., for at least 1 hour.

[0119] Collect the ethereal phase in a corresponding 5 ml borosilicatetest tube.

[0120] Completely evaporate the ethereal phase using theevaporator+water bath system at 37° C.

[0121] Separation of the DHT

[0122] Preparation of the columns: Prepare the columns in 5 ml glassculture pipettes with 10 cm of chromatolithe A.

[0123] Rinsing of the columns: 3 ml of combitips pure isooctane (3times), allowing it to flow by mere gravity.

[0124] Elution of the dry ethereal extracts

[0125] Each dry extract is taken up in 1 ml of pure isooctane, vortexvigorously.

[0126]  Wait for 15 min at room temperature. Vortex again.

[0127] When the 3 ml of isooctane (washing of the columns) have beeneluted, pour the dry ethereal extracts taken up in isooctane over thecolumn. Allow to elute.

[0128] Rinse each “dry extract” tube with 1 ml of combitips pureisooctane, vortex vigorously. Wait for 15 min at room temperature.Vortex again and pour into the column as above.

[0129] Wash with 4 ml of pure isooctane.

[0130] Collect the DHT

[0131] Prepare the elution solvent (mixture containing 6%isooctane/ethyl acetate: 94/6 (v-v))

[0132] Elute with 6 ml (pipette) of this mixture.

[0133] Collect the DHT eluate in the 5 ml borosilicate test tubesidentified.

[0134] Treatment of the DHT eluate: Evaporate the eluate solvent usingthe evaporator-water bath system (37° C.)

[0135] RIA Assay

[0136] Distribution protocol: Take up the samples with 0.5 ml of RCbuffer, the Blank with 1 ml of Rcet buffer, the Controls with 0.5 ml ofRC buffer. Place in an oven at 37° C. for 15 min Shake the tubes againon coming out of the oven (1 min).

[0137]  In the identified 5 ml glass hemolysis tubes, place in order:

[0138] Buffer: Total Activity (TA): 0.7 ml of RC buffer, NonspecificActivity (N): 0.2 ml of RC buffer, Range: only point 0 of the range(note BO) contains 0.1 ml of RC buffer,

[0139] Standard solution (1 000 to 7.8 pg/tube): 0.1 ml of therespective standard solution.

[0140] 0.1 ml of dry extract taken up in the buffer

[0141] Then, distribute the antiserum: 0.1 ml in all the tubes except TAand N.

[0142] Then, distribute the assay solution “3HD”: 0.1 ml in all thetubes.

[0143] Vortex and cover with parafilm.

[0144] Incubation at 4° C. for 1 h 30 min minimum (24 h maximum).

[0145] Preparation of the charcoal-dextran: place the charcoal-dextransuspension in a beaker, then in an ice-cold water bath at 4° C., for atleast 1 h 30 min.

[0146] DHT purification yield

[0147] In 6 small scintillation flasks (3 per series) deposit: 0.4 ml ofRC buffer +0.1 ml of “3H-Rdt” solution (flask from the first day in therefrigerator). Blanks: place 0.5 ml of reconstituted dry extract for theblank. Samples and controls: place 0.25 ml of RC buffer +0.25 ml ofextract.

[0148] Add 5 ml of scintillation liquid to all the flasks.

[0149] Separation of the Free DHT From That Bound to the Antibody

[0150] Place the charcoal-dextran suspension under magnetic stirring ina basin of ice-cold water.

[0151] Add 0.5 ml of charcoal-dextran to all the tubes except TA over 2min maximum.

[0152] Vortex, return the tubes to the ice-cold water. Wait for exactly10 min. Centrifuge at 4° C., 3 400 rpm, for 11 min

[0153] Pipette 0.5 ml of each supernatant (including TA) into a smallcounting flask

[0154] Add 5 ml of scintillation liquid. Stir, allow to equilibrate for30 min at room temperature.

[0155] Count for 2 min with the β counter (Beckman, LS 6000 SE).

[0156] 2. Results

[0157] 2.1 Evaluation of the Conversion of Testosterone to5-Dihydrotestosterone by the DU 145 Cells—Determination of the IC 50Values TABLE 5 Product tested IC 50 (μg/ml) Fatty acids of avocado oil(1) 510 Methyl esters of avocado oil (1)  13 Methyl esters of soybeanoil (1) 304 Methyl oleate (2) 386 Serenoa repens  60

[0158] (1) obtained as described in example 1

[0159] (2) commercial product (Sigma, 99% purity)

[0160] 3. Conclusions

[0161] In general, the methyl esters of fatty acids exhibit a5α-reductase inhibitory activity.

[0162] Among them, the methyl esters of avocado oil constitute the mostactive product. They are 5 to 6 times more active than the Serenoarepens extract, a recognized 5α-reductase inhibitor.

[0163] The methyl esters of avocado oil are more active than theirsoybean oil homologues.

[0164] The methyl esters of avocado exhibit a 5-alpha-reductaseinhibitory activity unlike their precursors, the fatty acids of avocado,which exhibit a markedly lower activity on this enzyme.

[0165] Finally, methyl oleate, predominant constituent of the methylesters of avocado (50%), tested alone, proves markedly less active thanthe methyl esters of avocado.

Example 3 Evaluation in vitro of the 5-αReductase Activity on theConversion of Testosterone to 5α-Dihydrotestosterone in Cultures ofNormal Human Dermal Fibroblasts.

[0166] Abbreviations used in the Following Examples:

[0167]³H: tritium

[0168] TLC: thin-layer chromatography

[0169] Ci: Curie

[0170] DMSO: dimethyl sulfoxide

[0171] M199: name given to a standard culture medium

[0172] FCM: fibroblast culture medium

[0173] MEM: name given to the culture medium Minimum Essential Medium

[0174] FIM: fibroblast incubation medium

[0175] Rf: relative retardation factor

[0176] FCS: fetal calf serum

[0177] 5α-DHT: 5α-dihydrotestosterone

[0178] It is proposed to evaluate the effect of the products such asmethyl oleate (Sigma commercial product, 99% purity), of the methylesters of avocado and of a Serenoa Repens extract chosen as reference onthe 5α-reductase activity. An in vitro model of normal human dermalfibroblast cultures was selected.

[0179] 1. Materials and Methods

[0180] 1.1 Test Products, Reference Product, and Reagents

[0181] The test products were provided by EXPANSCIENCE and were storedat +4° C. until the time of their use. The radioactive testosterone(labeled with tritium at the 1, 2, 6 and 7 position, specific activity79 Ci/mmol) was provided by AMERSHAM, the nonradiolabeled testosteronewas provided by SIGMA.

[0182] The reagents of analytical grade, were obtained from SIGMA,MERCK, BDH, ALDRICH or CARLO ERBA unless otherwise stated.

[0183] 1.2 Assay System

[0184] The fibroblast culture medium (FCM) consisted of MEM/M199 (3:1,v/v) supplemented with penicillin (50 IU/ml), streptomycin (50 μg/ml),sodium bicarbonate (0.2%, w/v) and FCS (10%, v/v).

[0185] The assay system consisted of normal human dermal fibroblastscultured as a monolayer. The fibroblasts were isolated from a residuefrom abdominal plastic surgery performed on a 51 year old female(subject BIOPREDIC No. I0013). The cells were used at the fifth passage;they were cultured until the monolayers were confluent in FCM medium at37° C. in a humid atmosphere containing 5% CO₂.

[0186] 1.3 Preparation of the Products and Incubation with the AssaySystem

[0187] The fibroblast incubation medium (FIM) consisted of FCMsupplemented with tritiated testosterone (1.6×10⁻⁷ M, that is 6.32μCi/ml) and nonradiolabeled testosterone (3.84×10⁻⁶ M)

[0188] The test products and finasteride were taken up in DMSO beforebeing diluted in the incubation medium. The final concentration of DMSOwas kept constant and equal to 1% (v/v) in each dilution of testproducts and reference products. Time scale:

removal of the FCM medium

preincubation of the test products and reference product prepared in theFCM medium

removal of the FCM media containing the test products or the referenceproduct

incubation of the test products and of the reference product prepared inthe FIM medium

determination of the 5α-reductase activity.

[0189] The fibroblast cultures were preincubated in the presence of thetest products or of the reference product for 2 hours before adding thesubstrate, testosterone. For this step, the test products and thereference product were prepared in the FCM medium.

[0190] After preincubation, the fibroblast cultures were incubated inthe presence of the test products or of the reference product preparedin the FIM medium for 22 hours at 37° C. in a humid atmospherecontaining 5% CO₂. Control cultures were incubated in the FIM medium inthe absence of test products and of reference product. “DMSO control”cultures were incubated in the FIM medium containing 1% (v/v) of DMSO.

[0191] Each experimental condition was tested in triplicate.

[0192] 1.4 Evaluation of the Effects

[0193] After the incubation period, the cells were subjected to theaction of ultrasound in the FIM medium. The cellular lysates thusobtained were extracted with dichloromethane. After evaporation, the dryresidues were taken up in methanol and were deposited on 60F₂₅₄ silicaplates (MERCK, reference 5554).

[0194] Nonradiolabeled standards, testosterone, 5α-dihydro-testosteroneand androstenedione, were deposited on each of the plates.

[0195] The migration solvent was a mixture of dichloromethane and ether(7:3, v/v) At the end of the migration, the silica plates were readusing a BERTHOLD radioactivity scanner.

[0196] The nonradiolabeled standards were visualized by spraying 5%sulfuric acid (v/v) over the chromatography plates which were thenheated at 100° C. for 10 minutes.

[0197] Comparison of the Rf values (relative retardation factor)determined for the standards with those obtained for the variousradioactive metabolites allowed the identification of the latter.

[0198] The metabolizing of testosterone to 5α-dihydro-testosterone underthe various experimental conditions was calculated: the results (areasof the 5α-dihydrotestosterone peaks counted by the BERTHOLD scanner)were expressed in pmol of 5α-dihydro-testosterone formed per culturewell. They were also expressed as a percentage of the 5α-reductaseactivity present in the “DMSO control” group.

[0199] 1.5—Treatment of the Data

[0200] The groups of data (control group and treated groups) weretreated by a one-way analysis of variance (ANOVA 1, p<0.05), followed bya DUNNETT's test (p<0.05). The effect of the test products and of thereference product was compared with the “DMSO control” group. Theeffects of the test products were compared to each other by a two-wayanalysis of variance (ANOVA 2, p<0.05, factor 1=concentration and factor2=treatment).

[0201] 2. Results and Discussion

[0202] In the control cultures, the rate of testosterone metabolism was9.71+/−0.77 pmol of 5α-DHT formed in 22 hours per culture well. Thisrate was in conformity with the results already obtained in thelaboratory.

[0203] The methyl esters of avocado, tested at 10 and 100 μg/ml,inhibited the 5α-reductase activity by 29 and 55% respectively (table6).

[0204] The purified methyl oleate, tested at 1, 10 and 100 μg/ml,inhibited the 5α-reductase activity by 24, 38 and 41% respectively(table 7).

[0205] The Serenoa Repens extract, reference product, tested at 10 and100 μg/ml, inhibited the 5α-reductase activity by 15 and 35%respectively. At 1 μg/ml, it had no effect (table 7).

[0206] In conclusion, the products tested inhibited the 5α-reductaseactivity.

[0207] Depending on the activity of the test products, tested at 10 and100 μg/ml, the methyl esters of avocado and the purified methyl oleateexhibited a 5α-reductase inhibitory activity significantly higher thanthat of the Serenoa repens extract, chosen as reference.

[0208] This test therefore confirms the inhibitory activity of themethyl esters of fatty acids, and in particular those of avocado oil.

[0209] 3. Tables

[0210] 3.1—Effect of the Methyl Esters of Avocado on the 5α-ReductaseActivity in Normal Human Dermal Fibroblast Cultures After 22 Hours ofIncubation TABLE 6 DMSO Concentration (μg/ml) Product 1% (v/v) 10 100Methyl 8.00 5.80 4.28 esters of 8.92 6.36 2.72 avocado 8.68 6.08 4.488.53 +/− 0.48 6.08* +/− 0.28 3.83* +/− 0.96 100    71    45   

[0211] 3.2—Effect of Methyl Oleate and of the Serenoa Repens Extract onthe 5α-Reductase Activity in Normal Human Dermal Fibroblast Culturesafter 22 Hours of Incubation. TABLE 7 DMSO Concentration (μg/ml) Product1% (v/v) 1 10 100 Methyl 8.00 7.12 3.00 5.44 oleate 8.92 6.24 7.04 5.128.68 6.08 5.92 4.60 8.53 +/− 6.48* +/− 5.32* +/− 5.05* +/− 0.48 0.562.09 0.42 100 76 62 59 Serenoa 8.00 7.72 6.84 5.48 Repens 8.92 9.20 7.485.68 extract 8.68 8.08 7.52 5.44 8.53 +/− 8.33 +/− 7.28* +/− 5.53* +/−0.48 0.77 0.38 0.13 100 98 85 65

Example 4 Evaluation in vitro of Fatty Acid Esters on the 5α-ReductaseActivity for the Conversion of Testosterone to 5α-Dihydrotestosterone inNormal Human Dermal Fibroblast Cultures

[0212] 1. Materials and Methods

[0213] The same materials and methods are used as in example 3 above.

[0214] 2—Results and Discussion

[0215] It was proposed to evaluate the effect of fatty acid esters onthe 5α-reductase activity. An in vitro model of normal human dermalfibroblast cultures was selected. The products tested were chosen fromthe group of fatty acid esters varying in the length and thefunctionality of the fatty chain, and the nature of the alkoxy group.These esters are the following: methyl oleate, methyl linoleate, methylstearate, methyl laurate, methyl undecylenate, butyl oleate, oleyloleate and methyl ricinoleate.

[0216] Methyl oleate, tested at 1, 10 and 100 μg/ml, significantlyinhibited (p<0.05) the 5α-reductase activity by 29%, 42% and 26%respectively.

[0217] Oleyl oleate, tested at 1, 10 and 100 μg/ml, significantlyinhibited (p<0.05) the 5α-reductase activity by 28%, 45% and 35%respectively. At 10 and 100 μg/ml, the fibroblasts exhibited cellularsuffering observed by morphological examination of the cells.

[0218] Butyl oleate, tested at 1, 10 and 100 μg/ml, significantlyinhibited (p<0.05) the 5α-reductase activity by 21%, 45% and 49%respectively.

[0219] Methyl undecylenate, tested at 1, 10 and 100 μg/ml, significantlyinhibited (p<0.05) the 5α-reductase activity by 40%, 32% and 26%respectively.

[0220] Methyl stearate, tested at 1, 10 and 100 μg/ml, significantlyinhibited (p<0.05) the 5α-reductase activity by 41%, 35% and 43%respectively.

[0221] Methyl linoleate, tested at 1, 10 and 100 μg/ml, significantlyinhibited (p<0.05) the 5α-reductase activity by 42%, 40% and 29%respectively.

[0222] Methyl ricinoleate, tested at 1, 10 and 100 μg/ml, significantlyinhibited (p<0.05) the 5α-reductase activity by 37%, 38% and 62%respectively.

[0223] In conclusion, under the experimental conditions selected,depending on the activity of the test products, tested at 1, 10 and 100μg/ml, it was possible to classify the test products into three groups:

[0224] Methyl oleate, butyl oleate, oleyl oleate and methylricinoleate=group A with the highest inhibitory activity. Methyllinoleate, stearate, laurate and undecylenate=group B with anintermediate inhibitory activity.

[0225] The products of group A exhibited a 5α-reductase inhibitoryactivity significantly (p<0.05) greater than that of the products ofgroup B.

[0226] Within the group, the products had a comparable inhibitoryactivity.

[0227] 2—Detailed Tables of Results: Effect of Fatty Acid Esters the5α-Reductase Actvivity in Normal Human Dermal Fibrolast Cultures, After24 of Incubation TABLE 8 DMSO Concentration (μg/ml) Product 0.1% (v/v) 110 100 Methyl oleate  10.56  8.24  6.28  7.52  12.00  8.28  6.44  7.00 11.64  7.84  7.12  7.20  11.40 +/−  8.12* +/−  6.61* +/−  7.24* +/− 0.75  0.24  0.45  0.26 100 71 58 64 Oleyl oleate  10.56  9.00  6.12 6.28  12.00  7.32  6.44  8.60  11.64  8.20  6.20  7.48  11.40 +/− 8.17* +/−  6.25* +/−  7.45* +/−  0.75  0.84  0.17  1.16 100 72 55 65Butyl oleate  10.56 10.64  6.24  5.20  12.00  8.28  5.04  6.72  11.64 8.08  7.36  5.40  11.40 +/−  9.00* +/−  6.21* +/−  5.77* +/−  0.75 1.42  1.16  0.83 100 79 55 51 Methyl  10.56  6.56  7.68  8.68undecylenate  12.00  7.44  7.84  7.76  11.64  6.68  7.60  9.00  11.40+/−  6.89* +/−  7.71* +/−  8.48* +/−  0.75  0.48  0.12  0.64 100 60 6874 Methyl  10.56  6.92  8.80  6.88 stearate  12.00  6.08  6.72  5.92 11.64  7.08  6.76  6.76  11.40 +/−  6.69* +/−  7.43* +/−  6.52* +/− 0.75  0.54  1.19  0.52 100 59 65 57 Methyl  10.56  7.04  6.00  8.56linoleate  12.00  6.40  6.60  8.04  11.64  6.36  8.00  7.56  11.40 +/− 6.60* +/−  6.87* +/−  8.05* +/−  0.75  0.38  1.03  0.50 100 58 60 71Methyl  10.56  6.52  7.84  3.68 ricinoleate  12.00  8.36  7.40  4.52 11.64  6.68  5.88  4.80  11.40 +/−  7.19* +/−  7.04* +/−  4.33* +/− 0.75  1.02  1.03  0.58 100 63 62 38 Methyl  10.56  5.76  6.84  8.48laurate  12.00  6.88  9.88 11.96  11.64  6.84  9.52  8.96  11.40 +/− 6.49* +/−  8.75 +/−  9.80 +/−  0.75  0.64  1.66  1.89 100 57 77 86

Example 6 Composition of Hyperseborrhea Cream

[0228] % by weight Butyl esters of avocado oil 15.0  Staryl alcohol 3.0Steareth-21 3.0 Steareth-2 2.0 Water qs 100 Carbopol 0.4 Sodiumhydroxide 0.3 Butylated hydroxytoluene (BHT) 0.4 Perfume 0.1 100%    

1. The use of at least one fatty ester whose fatty chain is a linearC₇-C₃₀ hydrocarbon chain containing between 0 and 2 ethylenicunsaturations and being capable of being substituted with 1 to 3hydroxyl groups and/or 1 to 3 ester functional groups in addition to theprincipal ester functional group for the preparation of a compositiondesigned to inhibit 5α-reductase activity.
 2. The use as claimed inclaim 1, characterized in that the composition is designed to inhibitthe 5α-reductase type 1 isoenzyme and/or type 2 isoenzyme.
 3. The use asclaimed in claim 1 or 2, characterized in that the ester functionalgroup comprising a C₁-C₃₀ alkoxy group whose hydrocarbon chain is linearor branched, optionally substituted with 1 to 3 hydroxyl groups.
 4. Theuse as claimed in any one of claims 1 to 3, characterized in that thefatty chain is an ethylenically unsaturated linear C₇-C₃₀ hydrocarbonchain comprising 1 or 2 ethylenic unsaturations.
 5. The use as claimedin any one of the preceding claims, characterized in that the fattyester is obtained by esterification of at least one fatty acid of atleast one vegetable oil.
 6. The use as claimed in any one of thepreceding claims, characterized in that the fatty ester is obtained bytransesterification of triglycerides of at least one vegetable oil. 7.The use as claimed in any one of the preceding claims, characterized inthat the fatty ester is chosen from the group consisting of fatty estersof avocado oil, or soybean oil and mixtures thereof.
 8. The use asclaimed in claim 7, characterized in that the fatty ester consists ofalkyl esters of avocado oil, alkyl esters of soybean oil, or of amixture thereof.
 9. The use as claimed in claim 7 or 8, characterized inthat the fatty ester consists of methyl esters of avocado oil, methylesters of soybean oil, or of a mixture thereof.
 10. The use as claimedin claim 7 or 8, characterized in that the fatty ester consists of butylesters of avocado oil, butyl esters of soybean oil, or of a mixturethereof.
 11. The use as claimed in any one of claims 1 to 6,characterized in that the fatty ester is chosen from the groupconsisting of methyl oleate, methyl linoleate, methyl stearate, methyllaurate, methyl undecylenate, butyl oleate, oleyl oleate, methylricinoleate, methyl palmitate, methyl palmitoelate, and mixturesthereof.
 12. The use as claimed in any one of claims 1 to 6,characterized in that the fatty ester is butyl oleate.
 13. The use asclaimed in any one of claims 1 to 6, characterized in that the fattyester is methyl ricinoleate.
 14. The use as claimed in any one of thepreceding claims, characterized in that the fatty ester is used in aproportion of between about 0.001 and about 100% by weight, relative tothe total weight of the composition.
 15. The use as claimed in any oneof the preceding claims, characterized in that the composition preparedcomprises a pharmaceutically, dermatologically or cosmeticallyacceptable excipient.
 16. The use as claimed in claim 15, characterizedin that the excipient is suitable for administration by the externaltopical route or by the rectal route.
 17. The use as claimed in any oneof the preceding claims, characterized in that the composition isdesigned for treating skin pathologies and/or disorders related tocongenital or acquired exaggeration of the 5α-reductase activity. 18.The use as claimed in any one of claims 1 to 16, characterized in thatthe composition is designed for treating prostatic hypertrophy.
 19. Theuse as claimed in any one of claims 1 to 16, characterized in that thecomposition is designed for treating prostatic adenoma.
 20. The use asclaimed in any one of claims 1 to 16, characterized in that thecomposition is designed for treating acne.
 21. The use as claimed in anyone of claims 1 to 16, characterized in that the composition is designedfor treating hyperseborrhea.
 22. The use as claimed in any one of claims1 to 16, characterized in that the composition is designed for treatingalopecia.
 23. The use as claimed in any one of claims 1 to 16,characterized in that the composition is designed for treatinghirsutism.
 24. A method for the cosmetic treatment of greasy skin,characterized in that a cosmetic composition containing at least onefatty ester as defined in claim 1 is applied to the skin.
 25. A methodfor the cosmetic treatment of hair loss, characterized in that acosmetic composition containing at least one fatty ester as defined inclaim 1 is applied to the scalp.
 26. A method for the cosmetic treatmentof excess pilosity, characterized in that a cosmetic compositioncontaining at least one fatty ester as defined in claim 1 is applied tothe regions of the skin exhibiting excess pilosity.
 27. The method ofcosmetic treatment as claimed in any one of claims 24 to 26,characterized in that the fatty ester is as defined in any one of claims3 to
 13. 28. The method of cosmetic treatment as claimed in any one ofclaims 24 to 26, characterized in that the fatty ester is present in thecomposition in a proportion of between about 0.001 and about 100% byweight, relative to the total weight of the composition.
 29. The methodas claimed in any one of claims 24 to 26, characterized in that thecosmetic composition contains, in addition, at least one cosmeticallyacceptable excipient.
 30. The use of at least one fatty ester as definedin claim 1 as additive in a food product for human and/or animalconsumption.
 31. The use as claimed in claim 30, characterized in thatthe fatty ester is as defined in any one of claims 3 to
 13. 32. The useas claimed in claim 30 or 31, characterized in that the fatty ester ispresent in the food in a proportion of between about 0.001 and about100% by weight, relative to the total weight of the food.